// -*- coding: utf-8 -*-
// Copyright (C) 2011, 2012, 2013, 2014 Laboratoire de Recherche et
// Développement de l'Epita (LRDE).
// Copyright (C) 2003, 2004, 2005 Laboratoire d'Informatique de Paris
// 6 (LIP6), département Systèmes Répartis Coopératifs (SRC),
// Université Pierre et Marie Curie.
//
// This file is part of Spot, a model checking library.
//
// Spot is free software; you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 3 of the License, or
// (at your option) any later version.
//
// Spot is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
// or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
// License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

#include "lbtt.hh"
#include <map>
#include <string>
#include <ostream>
#include "tgba/formula2bdd.hh"
#include "reachiter.hh"
#include "misc/bddlt.hh"
#include "priv/accmap.hh"
#include "ltlvisit/lbt.hh"
#include "ltlparse/public.hh"

namespace spot
{
  namespace
  {
    // At some point we'll need to print an acceptance set into LBTT's
    // format.  LBTT expects numbered acceptance sets, so first we'll
    // number each acceptance condition, and later when we have to print
    // them we'll just have to look up each of them.
    class acceptance_cond_splitter
    {
    public:
      acceptance_cond_splitter(bdd all_acc)
      {
	unsigned count = 0;
	while (all_acc != bddfalse)
	  {
	    bdd acc = bdd_satone(all_acc);
	    all_acc -= acc;
	    sm[acc] = count++;
	  }
      }

      std::ostream&
      split(std::ostream& os, bdd b)
      {
	while (b != bddfalse)
	  {
	    bdd acc = bdd_satone(b);
	    b -= acc;
	    os << sm[acc] << ' ';
	  }
	return os;
      }

    private:
      typedef std::map<bdd, unsigned, bdd_less_than> split_map;
      split_map sm;
    };

    class lbtt_bfs : public tgba_reachable_iterator_breadth_first
    {
    public:
      lbtt_bfs(const const_tgba_ptr& a, std::ostream& os, bool sba_format)
	: tgba_reachable_iterator_breadth_first(a),
	  os_(os),
	  all_acc_conds_(a->all_acceptance_conditions()),
	  acs_(all_acc_conds_),
	  sba_format_(sba_format),
	  // Check if the automaton can be converted into a
	  // tgba_digraph. This makes the state_is_accepting()
	  // function more efficient.
	  sba_(std::dynamic_pointer_cast<const tgba_digraph>(a))
      {
	if (sba_ && !sba_->get_bprop(tgba_digraph::SBA))
	  sba_ = nullptr;
      }

      bool
      state_is_accepting(const state *s) const
      {
	// If the automaton has a SBA type, it's easier to just query the
	// state_is_accepting() method.
	if (sba_)
	  return sba_->state_is_accepting(s);

	// Otherwise, since we are dealing with a degeneralized
	// automaton nonetheless, the transitions leaving an accepting
	// state are either all accepting, or all non-accepting.  So
	// we just check the acceptance of the first transition.  This
	// is not terribly efficient since we have to create the
	// iterator.
	tgba_succ_iterator* it = aut_->succ_iter(s);
	bool accepting = it->first()
	  && it->current_acceptance_conditions() == all_acc_conds_;
	aut_->release_iter(it);
	return accepting;
      }


      void
      process_state(const state* s, int n, tgba_succ_iterator*)
      {
	--n;
	if (n == 0)
	  body_ << "0 1";
	else
	  body_ << "-1\n" << n << " 0";
	// Do we have state-based acceptance?
	if (sba_format_)
	  {
	    // We support only one acceptance condition in the
	    // state-based format.
	    if (state_is_accepting(s))
	      body_ << " 0 -1";
	    else
	      body_ << " -1";
	  }
	body_ << '\n';
      }

      void
      process_link(const state*, int,
		   const state*, int out, const tgba_succ_iterator* si)
      {
	body_ << out - 1 << ' ';
	if (!sba_format_)
	  {
	    acs_.split(body_, si->current_acceptance_conditions());
	    body_ << "-1 ";
	  }
	const ltl::formula* f = bdd_to_formula(si->current_condition(),
					       aut_->get_dict());
	to_lbt_string(f, body_);
	f->destroy();
	body_ << '\n';
      }

      void
      end()
      {
	os_ << seen.size() << ' ';
	if (sba_format_)
	  os_ << '1';
	else
	  os_ << aut_->number_of_acceptance_conditions() << 't';
	os_ << '\n' << body_.str() << "-1" << std::endl;
      }

    private:
      std::ostream& os_;
      std::ostringstream body_;
      bdd all_acc_conds_;
      acceptance_cond_splitter acs_;
      bool sba_format_;
      const_tgba_digraph_ptr sba_;
    };

    static
    tgba_digraph_ptr
    lbtt_read_tgba(unsigned num_states, unsigned num_acc,
		   std::istream& is, std::string& error,
		   const bdd_dict_ptr& dict,
		   ltl::environment& env, ltl::environment& envacc)
    {
      auto aut = make_tgba_digraph(dict);
      acc_mapper_int acc_b(aut, num_acc, envacc);
      aut->new_states(num_states);

      for (unsigned n = 0; n < num_states; ++n)
	{
	  int src_state = 0;
	  int initial = 0;
	  is >> src_state >> initial;
	  if (initial)
	    aut->set_init_state(src_state);

	  // Read the transitions.
	  for (;;)
	    {
	      int dst_state = 0;
	      is >> dst_state;
	      if (dst_state == -1)
		break;

	      // Read the acceptance conditions.
	      bdd acc = bddfalse;
	      for (;;)
		{
		  int acc_n = 0;
		  is >> acc_n;
		  if (acc_n == -1)
		    break;
		  auto p = acc_b.lookup(acc_n);
		  if (p.first)
		    {
		      acc |= p.second;
		    }
		  else
		    {
		      error += "more acceptance sets used than declared";
		      return nullptr;
		    }
		}

	      std::string guard;
	      std::getline(is, guard);
	      ltl::parse_error_list pel;
	      const ltl::formula* f = parse_lbt(guard, pel, env);
	      if (!f || !pel.empty())
		{
		  error += "failed to parse guard: " + guard;
		  if (f)
		    f->destroy();
		  return nullptr;
		}
	      bdd cond = formula_to_bdd(f, dict, aut.get());
	      f->destroy();
	      aut->new_transition(src_state, dst_state, cond, acc);
	    }
	}
      return aut;
    }

    tgba_digraph_ptr
    lbtt_read_gba(unsigned num_states, unsigned num_acc,
		  std::istream& is, std::string& error,
		  const bdd_dict_ptr& dict,
		  ltl::environment& env, ltl::environment& envacc)
    {
      auto aut = make_tgba_digraph(dict);
      acc_mapper_int acc_b(aut, num_acc, envacc);
      aut->new_states(num_states);
      aut->set_bprop(tgba_digraph::StateBasedAcc);

      for (unsigned n = 0; n < num_states; ++n)
	{
	  int src_state = 0;
	  int initial = 0;
	  is >> src_state >> initial;
	  if (initial)
	    aut->set_init_state(src_state);

	  // Read the acceptance conditions.
	  bdd acc = bddfalse;
	  for (;;)
	    {
	      int acc_n = 0;
	      is >> acc_n;
	      if (acc_n == -1)
		break;
	      auto p = acc_b.lookup(acc_n);
	      if (p.first)
		{
		  acc |= p.second;
		}
	      else
		{
		  error += "more acceptance sets used than declared";
		  return nullptr;
		}
	    }

	  // Read the transitions.
	  for (;;)
	    {
	      int dst_state = 0;
	      is >> dst_state;
	      if (dst_state == -1)
		break;

	      std::string guard;
	      std::getline(is, guard);
	      ltl::parse_error_list pel;
	      const ltl::formula* f = parse_lbt(guard, pel, env);
	      if (!f || !pel.empty())
		{
		  error += "failed to parse guard: " + guard;
		  if (f)
		    f->destroy();
		  return nullptr;
		}
	      bdd cond = formula_to_bdd(f, dict, aut.get());
	      f->destroy();
	      aut->new_transition(src_state, dst_state, cond, acc);
	    }
	}
      return aut;
    }

  } // anonymous


  std::ostream&
  lbtt_reachable(std::ostream& os, const const_tgba_ptr& g, bool sba)
  {
    lbtt_bfs b(g, os, sba);
    b.run();
    return os;
  }


  tgba_digraph_ptr
  lbtt_parse(std::istream& is, std::string& error, const bdd_dict_ptr& dict,
	     ltl::environment& env, ltl::environment& envacc)
  {
    is >> std::skipws;

    unsigned num_states = 0;
    is >> num_states;
    if (!is)
      {
	error += "failed to read the number of states";
	return 0;
      }

    // No states?  Read the rest of the line and return an empty automaton.
    if (num_states == 0)
      {
	std::string header;
	std::getline(is, header);
	return make_tgba_digraph(dict);
      }

    unsigned num_acc = 0;
    is >> num_acc;

    int type;
    type = is.peek();
    if (type == 't' || type == 'T' || type == 's' || type == 'S')
      type = is.get();

    if (type == 't' || type == 'T')
      return lbtt_read_tgba(num_states, num_acc, is, error, dict,
			    env, envacc);
    else
      return lbtt_read_gba(num_states, num_acc, is, error, dict,
			   env, envacc);
  }
}